Valve control apparatus



Jan. 12, 1937. D L, SMlTH 2,067,622

VALVE CONTROL APPARATUS Filed April 4, 1935 2 Sheets-Sheet 1 lgENToRATTORNEY Jan. 12, 1937. D. 1.. SMITH VALVE CONTROL APPARATUS Filed April4, 1935 2 Sheets-Sheet 2 ATTORNEY Patented Jan. 12, 1937 UNITED STATESPATENT OFFICE VALVE CONTROL APPARATUS Donald L. Smith, Caldwell, N. J.,assignor to Air Reduction Company, Incorporated, New York, N. Y., acorporation of New York Application April 4, 1935, Serial No. 14.657

10 Claims. (01. 158-274) This invention relates to valve apparatus forAnother object of the invention is to provide controlling the flow offluid through pipes or a novel shut-oil valve for controlling the supplyconduits, and more particularly to valve apof gas to a torch in responseto the movement of paratus for the protection of oxy-fuel-gas supplyswitches in electric control circuits. lines and acetylene lines. Otherobjects, features and advantages of the 5 It is an object of theinvention to provide invention will appear or be pointed out as theimproved control apparatus which operates in specification proceeds.

response. to a sudden change in pressure in a In the accompanyingdrawings, forming part conduit to close a valve and shut off the flow ofhereof: fluid through the conduit. The change in-pres- Fig. 1 is a view,partly diagrammatic and 19 sure may be a sudden increase caused by anexpartly. in section, showing torch control applosion of acetylene, orflash-back at a burner paratus embodying the invention;

or torch, or may be a sudden decrease caused by Fig. 2 is an enlargedsectional view on the the bursting of a pipe, or hose, or by injury toline 2-2 of Fig. l;

some apparatus resulting in excessive leakage of Fig. 3 illustrates amechanical valve'operating 15 the gas. mechanism which can be employedin place of Another object of the invention is to provide the electriccontrol device shown in Figs. 1

improved apparatus for preventing damagefrom and 2;

flash-backs and back-fires of oxy-fuel-gas burn- Fig. 4 is a sectionalview taken on the line 44 ers or torches. In this specification the termof Fig. 2; and 20 flash-back" is used in a broad sense to include Fig. 5is a diagrammatic view showing an situations in which the flame flashesinto the embodiment of the invention for controlling two burner or torchtip and then ceases to burn, torches.

leaving the torch extinguished, or continues to Oxygen from a storagecylinder i0 is delivered burn within the'torch, but without travelingback through a regulator ii and conduit I2 to a through a gas conduit,and to include back-fires torch i4. Fuel gas is supplied to the torchfrom in which the flame does travel back through a a storage cylinder I!through a regulator Hi and gas delivery conduit. conduit IT. The storagecylinders are repre- According to one feature of the invention, thesentative of sources of gas. The torch I4 is supply of gas to the torchis automatically shut illustrated diagrammatically as a multi-flame 30oil in the event of a flash-back, and continued torch, but the inventionis applicable to any type burning of gas inside the torch, or travel ofa burner or torch in which oxygen and fuel gas flame back through a gasconduit, becomes im-, are mixed and discharged through flame jetpossible. I orifices.

Another object of the invention to provide The conduit for the fuel gasincludes a shut-off 35 means for preventing flash-backs at the timevalve 20 containing a valve element 2|. This the torch is lighted. Ifthe oxygen supply, is valve closes in the direction of the gas flow andturned on before the fuel gas, and the torch is is normally held closedby a spring 22 and the lighted as soon as the fuel gas begins to flow,upstream pressure of the gas.

40 the excess oxygen in the mixture causes a flame A solenoid 24,connected to the shut-off valve 40 propagation'which is at a higher ratethan the 20, operates a plunger 25. When the solenoid is gas flowthrough the torch orifices, with the renot energized; the plunger 25 isheld in an elesult that the flames flash back into the torch. vatedposition by a spring 26. Astem 21 extends If the oxygen and fuel gas areturned on at the downward from the solenoid to within a short same time,there may be excess oxygen in the distance of the stem of the valveelement 2|. 45 first gas to issue from the torch. If this is not Whenthe solenoid 24 is energized, it draws the the case, or if the lightingis delayed for an plunger 25 downward against the force of the instantuntil the mixture becomes correct, there spring 26 and causes the stem21 to move into is little danger of flash-backs, but the gas lightscontact with the stem of the valve element 2| with an objectionableexplosion. This invention and displace the stem so that the valve ismoved 50 insures against flash-backs at the time the torch into openposition. is lighted by preventing the oxygen from being The forcerequired to open the valve is greater supplied to the torch ahead of thefuel gas, or than the force required to hold it open because byrequiring that the fuel gas control valve be the gas pressure below thevalve element 2| reopened ahead of the oxygen control valve. sistsopening of the valve, but this pressure is 55 largely counterbalanced bythe gas pressure on the other side of the valve element after it ismoved into open position and gas is flowing around it. The gap betweenthe stem of the valve element 2| and the lower end of the stem 21permits the plunger 25 to start moving and gain considerable momentumbefore it encounters the resistance offered by the valve element. Theplunger stem 21 strikes a hammer blow against the stem of the valveelement 2| to impart the initial movement to the valve element. Thisfeature of the valve operating means makes possible the use of a smallersolenoid than would be required if there were no lost motion between theplunger and valve element. The force exerted by the solenoid is greaterif the stem 21 is made of non-magnetic material.

A safety device 30 includes a conduit pressure chamber 3| and acounterbalancing pressure chamber 32. The chamber 3| forms a part of theconduit through which the fuel is delivered to the torch. A diaphragm 35forms the top wall of the conduit pressure chamber 3|. A similardiaphragm 34 forms the bottom wall of the counterbalancing pressurechamber 32. The diaphragms 34 and 35 have their center portions clampedto a connector 36 so that any movement of either diaphragm istransmitted to the other.

The chambers 3| and 32 communicate through a conduit 38, which has a.restricted portion 40 for causing a time lag between a pressure changein the chamber 3| and a corresponding pressure change in thecounterbalancing pressure chamber. The length of this time lag dependson thesize of the restricted portion 46 of the conduit 38 and on thecapacity of the counterbalancing pressure chamber 32. An abutment 4|limits the upward movement of the diaphragms in case of a very suddenexcessive pressure rise in the conduit chamber 3|.

An electric switch 42 is supported between the diaphragms 34 and 35 byan arm 44, which is best shown in Figs. 2 and 4. The arm 44 is supportedat one end by a shaft 45; which extends through the end of this arm andthrough the casing of the safety device 30. The arm 44 has a limitedpivot movement about the axis of the shaft 45. The other end of the arm44 extends between opposing limit screws 46 and 41, which thread throughportions of the safety device 36 and are held in position by lock nuts46.

The free end of the arm 44 rests on the lowerlimit screw 46, and a leafspring 58, which is fastened to the arm, is confined between the arm andthe upper limit screw 41. The arm does not move during the ordinaryoperation of the safety device, but the spring will yield and permit theswitch and diaphragm to rise if the upward pressure of the diaphragm 35becomes so great that it is likely to damage the switch. The screw 46 isadjusted to bring the switch 42 into proper relation with the diaphragm35 and connector 36. The screw 41 is adjusted to obtain suflicienttension in the spring 50 to insure operation of the switch 42 before thespring yields.

The switch 42 is shown in Fig. 2 as a simple form of spring-operatedswitch with a fixed contact 52 connected to the switch housing,

which is of insulating material. A movable contact 53 is carried at oneend of a leaf spring 54 and the other end of this leaf spring is securedto the switch housing. The -tension of I with the control circuits.

the spring 54 normally holds the contact 63 against the contact 52. Apush rod 55 extends through the switch housing and contacts with thespring 54 close to its fixed end so that a small movement of the pushrod 55 causes a much larger movement at the contact end of the springand moves the contacts apart to open the circuit. In order that theswitch may be longer wearing, a snap-action switch may be employed. Thecurrent which passes through the switch is small, however, since it is arelay operating current and not'that supplied to the solenoids.

Fig. 1 shows the connection of the switch 42 The solenoids 24 and 29receive power through switches 51 and 58. Each of these switches is ofthe single-pole, double-throw type and when closed to the right directlyconnects its solenoid with the power line so that the solenoid remainsenergized regardless of the position of the control apparatus. When theswitch 51 is closed tothe left, the solenoid 24 is connected with thelower lefthand contact 60 of a relay 6|. Closing the switch 58 to theleft connects the solenoid 29 with the lower left-hand contact 63 of arelay- 64. When not energized, the relays 6| and 64 remain in the openpositions shown in Fig. 1;

When the relay 6| is energized, a contact bar 66 closes the circuitbetween the contact 60 and a contact 61 which connects with the powerline. A similar contact bar 68 closes the circuit between the contact 63and a contact 69 connected to the power line.

Both of the relays GI and 64 are connected with a conductor 10, whichconnects with the power line through a normally-closed switch 1|. Theother sides of the relays 6| and 64 are connected with conductors 13 and14, respectively. These conductors connect with a starting switch, whichincludes fixed contacts 15 and 16, movable contacts 11 and 18, and aplate 80 which is pivoted at its center so that it can be rocked. Theattendant rocks the plate 86 in a clockwise direction to move thecontact 11 against the contact 15. The. contact 15 is connected to theconductor 13, and the contact 11 connects with the return side of thepower line so that the power circuit through the relay 6| is completedand the relay energized when the contacts 15 and 11 are broughttogether.

When the attendant rocks the plate 86 counterclockwise, the contact 18is moved against the contact 16. These contacts 18 and 16 connect withthe conductors 14 and 13, respectively, but the power circuit of the'relay 64 is not completed when these contacts are brought togetherunless the relay 6| is already closed.

The movable contacts 11 and 18 spring away from the fixed contacts 15and 16 unless held against them by the plate 80. This plate comprises amanual switch-operating means which prevents the closing of the circuitsthrough the contacts 11 and 18 at the same time.

When the relay 6| is energized, it moves a contact bar 82 acrosscontacts 83 and 64, and completes a power circuit through the switch 42which is connected tothe contact 83 by a conductor 85. The circuit fromthe relay 6| throughthe switch 42 is a parallel circuit to that throughthe conductor 13 and contacts 15 and 11, and the relay 6| thereforeremains energized after the circuit through the contacts 15 and 11 isbroken.

The power circuit which the relay 64 extends from the power line throughthe switch conductor 16, relay 64, conductor 14, contacts 18 and I6,conductor 13, contact 84, contact bar 82, contact 63, conductor 85, andswitch 42. After the relay 64 has been energized it moves a contact bar81 against contacts 88 and 89 to close a circuit between these contactsand connect the relay 64 with the conductor 13 by a circuit parallel tothat through the contacts 16 and 18 so that when the attendant releasesthe plate 86, and the contact 18 moves away from the contact 16, therelay 64 will remain energized.

Fig. 3 shows a modified form of the invention in which the safety device96 controls the gas shut-oil? valve through a mechanical connectioninstead of an electric control. 'Most of the safety device 96 is similarin construction to the safety device 30, and corresponding parts areindicated by the same reference characters. A connector 9| is secured tothe diaphragms 34 and 35. A valve 92, controlling the supply of gasthrough the conduit I1, is connected to one end of a link 93 by a pinand slot connection 94. The other end of the link 93 is connected to thecasing of the safety device 96 by a pivot connection 95. A spring 96 isconnected at one end with the link 93 and at its other end with theconnector 9| at a point which locates the center line or line of pull ofthe spring 96 just below the axis of the pivot connection 96 when thepressure in the chambers 3| and 32 is substantially the same. With thespring 96 in such position, it tends to rotate the link 93 clockwise andthe link holds the valve 92 open.

A sudden increase in pressure in the conduit chamber 3| causes thediaphragm 35 to raise the connector 9|, and the end of the spring 96which is fastened to the connector, so that the line of pull of thespring is shifted to the other side of the pivot connection 95 and thespring tends to close the valve 92. When this valve is closed, the lineof force of the spring is further above the pivot 95 than its distancebelow the pivot when the valve is open. This construction permits asmall force to raise the connector 9| and close the valve 92, andobtains a strong force from the spring 96 to hold the valve closedagainst the gas pressure.

Fig. 5 shows the invention applied to the con-.- trol of two torches l4and I 6. All of the apparatus which is similar to that shown in Fig. 1is designated by the same reference characters as in Fig. 1. The oxygenand fuel gas are delivered to the torch l4 through conduits I2 and I1,respectively, which correspond to the conduits l2 and ll of the torchl4. Shut-off valves 26' and 26' in the conduits are controlled bysolenoids 24' and 28'. These valves and solenoids are similar to thoseshown in Fig. l, and

the solenoids are connected to the relays 6| and 66 in parallel with thesolenoids 24 and 29. Switches 51 and 58' are used to connect thesolenoids 24' and 29' directly to the power line or to the relays 6| and64 of the control circuits. A safety device 36 connected in the gas lineI1 and similar in construction to the safety device 39 has its switchconnected in series with the switch of the safety device 36 so thatopening of the switch in either of the safety devices 30 and 38'1 breaksthe power circuit through the relay 6|. The opening of the relay 6|breaks the power circuit through the relay 64. A switch 98 in serieswith the switch serves as a remote control for cutting of! the supply ofgas tothe torches.

The operation of the apparatus shown in Fig. 1 is as follows:

With the valves 26 and 28 closed and the switches 51 and 58 closed tothe left, the attendant starts the flow of gas to the torch l4 bytilting the plate 86 in a clockwise direction to move the contact 11against the contact 15. When these contacts come together, current flowsfrom the power line through the closed switch ll, conductor 10, relay6|, conductor 13, and contacts 15 and 11. The relay 6| is energized andmoves the contact bars 66 and 62 against their adjacent contacts.

When the contact bar 82 comes against the contacts 83 and 84, a circuitis closed from the relay 6| through the contact 64, contact bar 82,contact 63, conductor 65, and switch 42. This circuit is parallel tothat through the con tacts I5 and 11 and the relay 6| therefore remainsenergized after the attendant permits the contact 11 to move away fromthe contact I5.

When the contact bar 66 comes against the contacts 61 and 60, currentflows from the contact 61, through the contact bar 66, contact 60, andswitch 51, to the solenoid 24. The solenoid opens the valve 26 so thatfuel gas can flow to the torch |4. Since the initial fiow.of gas intothe conduit chamber 3| is likely to open the switch '42, the attendantshould hold the plate 88 depressed to the right to maintain the circuitthrough the contacts 15 and 11 until enough gas has flowed through theconduit 38 to substantially equalize the pressure in the chambers 3| and32.

The torch is lighted, and the plate 86 is rocked counter-clockwise tobring the contact 18 against the contact 16. Current flows from thepower line through the closed switch conductor 10, relay 64, conductor14, contacts 18 and 16, conductor 13, contact 84, contact bar 82,contact 63, conductor 65, and switch 42. The relay 64 is energized anddraws the contact bar 81 against the contacts 88 and 89 to establish acircuit between the conductors I3 and 14 which is parallel to thecircuit through the contacts I6 and 18 so that the relay 64 remainsenergized after the attendant releases the plate 88 and the contact I8moves away from the contact 16.

The relay 64 draws the contact bar 88 against the contacts 63 and 69, sothat current flows from the contact 69 through the contact bar 68,contact 63, and switch 56, to the solenoid 29. This solenoid, whenenergized, opens the valve 28 so that oxygen flows to the torch |4.

If there is a flash-back in the torch |4, there is a sudden increase inpressure in the conduit chamber 3| and the diaphragm 35 is flexed upwardand moves the connector 36 against the plunger of the switch 42,displacing the plunger and causing the switch to open and break thecircuits of both of the relays 6| and 64. As soon as current stopsflowing through these relays the contact bars 82, 66, 81 and 66 moveaway from their adjacent contacts, the supply of power to the solenoids24 and 29 is cut off, and the valves 26 and 28 close and shut off allgas to the torch. The valves 28 and 28 are preferably located close tothe torch so-that the volume of gas in the conduits between the valvesand the torch is'small. This gas expands after the valves close andprolongs the supply to the torch.

A short while after the switch 42 has been opened by a pressure increaseresulting from a flash-back, the gas'pressune. in the chambers 3| and 32becomes substantially equal and the switch 42 closes. The valves 20 and28 do not open, however, until the plate 80' is operated to againenergize the relays 6| and 64.

The switch H can be manually operated at any time to cut off the supplyof power to the relays and cause the valves 20 and 28 to close.

The operation of the control apparatus shown in Fig. 5 will be readilyunderstood from the foregoing description of Fig. 1. One special featureof the control apparatus in Fig. 5 is the connection of the switches ofthe safety devices 30 and 30- in series so that a flash-back at eithertorch causes the gas to both torches to be shut off. This feature isparticularly useful with installations where the two torches face oneanother and are close. together for heating the edges of a narrow, fiatskelp which is drawn between the torches. When the skelp is narrow andthe torches are close together, the flames of either torch are likely todamage the other if it is not lighted. In case of a flash-back whichextinguishes one torch, the control apparatus of Fig. 5 protects thetorch from injury by shutting off the supply of gas to the other torch.

The preferred embodiment and some modifications of the invention havebeen illustrated and described, but other modifications can be made andfeatures of the invention can be used without others.

I claim:

1. Apparatus for shutting off the flow of fluid through a supply line,including a normally closed valve in said line, a holding device formaintaining the valve in open position, and valve control means operatedby a sudden change of pressure in the conduit to release said holdingdevice so that the valve, if open, returns to its normally closedposition.

2. Apparatus for controlling the supply of gas to a torch, saidapparatus comprising a shut-oil valve in the conduit through which gasis delivered to the torch, a diaphragm exposed on one side to thepressure. in the conduit, a counterbalancing-pressure chamber on theother side of the diaphragm, a restricted port connecting said chamberwith the conduit, means mechanically independent of the diaphragm forholding the valve in open position, and means operated by movement ofthe diaphragm in response to the pressure rise caused by "aflash-backfor releasing the holding means and closing the shutoff valve.v

3. Apparatusfor controlling the operation of a torch, including aconduit for supplying gas to the torch, a sh'ut-ofi valve in theconduit, a diaphragm exposed on one side to the pressure in the conduit,and having a pressure-balancing chamber on its other. side with arestricted c-onduit through which gas flows to and from said chamber toequalize the pressure on both sides of the diaphragm, the rate of flowthrough said restricted conduit being small so that there is a time lagin the pressure equalization, and means operated by movement of saiddiaphragm in response to a sudden increase in pressure in the gas supplyconduit for causing the valve to close so that the supply of gas isautomatically cut off in the event of a flash-back at the torch.

4.,Apparatus for controlling the operation of a torch, including. a gasconduit for supplying oxygen to the'torch and another conduit forsupplying fuel gas to said torch, a shut-ofi valve in each of said gasconduits, a pressure-operated device connected with one of said conduitsand responsive to aflash-back of the torch, and 5 means operated by saidpressure-operated device to close the shut-oil valves in both conduitsin the event of a flash-back.

5. Control apparatus for a torch comprising separate valves forcontrolling the delivery of 10 oxygen and fuel gas to the torch,electric operating means for opening the oxygen valve, other electricoperating means for opening the fuel gas valve, switches for controllingthe .supply of power to the electric operating means, and con- 1.5nections between the circuits of said switches rendering the circuit ofthe oxygen valve operating means ineffective to cause the oxygen valvetoopen before the switch has been operated to cause the fuel gas valveto open. 20

6. Torch control apparatus comprising an oxygen shut-off valve, a fuelgas shut-off valve, an electric motor operatively connected to theoxygen valve to open said valve when the motor is energized, anothermotor similarly associated 25. with the fuel gas valve, amanually-operated switch in a circuit supplying power to the motor whichopens the fuel gas valve, and a second manually-operated switchfor'closing a circuit to the oxygen valve motor, the circuit of 30 saidsecond switch being connected to a source of power through the firstswitch so that the oxygen valve cannot be opened ahead of the fuel gasvalve. 7. Control apparatus which gas is delivered to a torch, includinga valve in the conduit, a diaphragm with one side exposed to thepressure of the gas in the conduit and the other side subject to thepressure in a pressure-balancing chamber which communi- 40 cates withthe conduit through a restricted outlet so that thei'e is a time lag inthe change of pressure in saijcl chamber in response to a pressurechange iii the conduit, means for holding the valve open means forclosing the valve, and 45 apparatus between the diaphragm and thevalveclosing means for making said valve-closing means operate'inresponse to a movement of the diaphragm byig, sudden rise in pressure inthe conduit. 5o

8. Control apparatus for a conduit through which gas is delivered to atorch, including a valve in the cohduit, a diaphragm with one sideexposedto the pressure of the gas in the conduit and the other sidesubject to the pressure in a pressure-balancing chamber whichcommunicates with the conduit through a restricted outlet so that thereis a time lag in the change of pressure in saidchamber in response to apres sure change in the conduit, electromagnetic means for holding thevalve open, a switch controlling the circuit of said electromagneticmeans, and motion-transmitting means operatively connected with thediaphragm and switch for opening said switch in response to a movementof the diaphragm by a sudden rise in pressure in the conduit.

9. Apparatus for controlling the-operation of a torch having conduitsfor delivering oxygen andfuel gas to said torch, said apparatus in 70cluding a shut-off valve in each of said conduits, control means foropening said valves, safety means operative in one position to preventthe control means from opening the oxygen valve,

and operative connections between the safety fora conduit through 35means and control means, said connections being constructed and arrangedto shift said safety a means into another position when said controlmeans is operated to operiathe fuel gas valve.

10. Control apparatus for a torch comprising separate valves forcontrolling the delivery of.

oxygen and fuel gas to the torch, means for apparatus to open the fuelgas valve closes said 5 portion of the circuit.

DONALD L. SMITH.

